Method of flattening end portions of a bar



Dec. 27, 1 938. H. G. wARR Er AL 2,141,576

METHOD OF FLATTENING END PORTIONS OF A BAR Filed April l5, 1936 jig Patented Dec.V 27, 1938 PATIENT oFFleE :METHOD OF FLATTENING END PORTIONS F A BAR Harold G. Warr, Park Ridge, Ill., and Richard A. v McLaughlin, Canton, Ohio, assignors, by mesne assignments, to Poor & Company, a corporation of Delaware Application April 13,

7 Claims.

having bowed or hook-shaped congurations.v

-The gradual decrease in the thickness of the ends of the bar permits. the Vmetal to be displacedwithout unduly weakening the end porv ltions of the bar.

When the ends of a heated bar are flattened.

simultaneously to form tapered end portions of :20 the character above mentioned, the attening pressure on the ends of the bar produces a compressive force lengthwise of the bar which tends to distort the intermediate portion of the bar in the directio-n of least resistance. The direction and form of such distortion depends largely upon the particular resistance offered by the individual bar being operated on. If the breadth of the bar is greater than its thickness and the flattening pressure is applied to the end po-rtions thereof in the direction of its breadth, the distortion in the bar will ordinarily take the form of a lateral bow in the direction of the thinner portion of the bar. This condition, however, may be altered by variations in the temperature at different locations on the bar and various other influences which may strengthen or weaken the resistance of the intermediate portion of the bar to the said lengthwise compressive force. Consequently, the amount and 40 direction of such distortioncannot be predetermined withdependable accuracy. The amount of distortion is, of course, more pronounced and consequently more objectionable in relatively short bars, since the amount or extent of distortion will ordinarily vary in proportion to the length of the bar.

In many instances, for example, in forming a bowed brace member or in forming devices such as rail anchors having hook-shaped jaws lprovided with flattenedl end bearings, it is important that the portion of the bar intermediate the flattened ends be entirely free of lateral or uncontrolled distortions so that the center of the attened end portions, when the bar is bent upon itself to form a hook configuration or return 1936, serial No. 74,128

bend, will coincide with the plane of the lo-ngitudinal center of the other portion of the bar. The fact that the amount and direction of such distortion may vary in bars of equal initial length, not only makes it impractical to establish uniform shop practice for straightening' the bars, lbut also makes it impractical to predetermine the exact length of the straightened or finished bars.

The principal object of this invention is to provide an improved method whereby both ends of a heated bar may be flattened simultaneously to form end portions which gradually increase in AWidth and decrease in thickness toward the ends of the bar and at the same time so control the extent and direction of any distortion of the intermediate portion of the bar by the compressive forces exerted lengthwise of the bar, as

tro'maintain the longitudinal center of the bar in Y a single vertical planel throughout the entire 'length r'of the bar during the said flattening operation.

According to the improved method a bar, suitably heated to facilitate attening of the ends is bent to provide a predetermined bow in` a denite direction during the application of flattening pressure to both of its end portions, thereby insuring that any distortion of the bar incident to the compressive force exerted lengthwise thereof during the simultaneous attening of the ends will follow the direction of and merge into the definite bend imparted to the bar. The arched or bowed configuration will be, therefore, uniform in all bars of equal length having corresponding flattened end portions. The flattening pressure is preferably applied to the bar at locations spaced from the extreme ends thereof so that unflattened portions Aat the extremities of the bar will provide lugs which engage the outer edges of the flattening implements and thereby -hold `the ends'of the bar from movement in the direction of its length during the flattening and bending operations.

After the ends of the bar havebeen flattened, the bar may be straightened, if desired, by applying suitable pressure to the crest of the bowed: intermediate portion; the flattened end portions serving to increase the elective width of the bar and thereby provide bases for preventing any tilting of the bar during the straightening operation or during the use of the bar in the variousr situations for which it is adapted. This straightlening operation can be performed either before or afterv the unflattened lug portions have been sheared from the bar.

The various steps of the improved method are illustrated in the accompanying drawing, where- Fig. 1 is a fragmentary view of cooperating die members showing the manner in which a heated bar is supported before the end attening pressure is applied thereto.

Fig. 2 is a view similar to Fig. 1 but showing the die` members in their innermost positions and illustrating the upwardly bowed coniiguration of the intermediate portion of the bar.

Fig. 3 is a plan view of the bar immediately after it has been removed from the dies of Fig. 2 and before the uniiattened end portions have been removed from the bar.

Fig. 4 and Fig. 5 are plan and side views respectively of the finished bar as it appears after the uniiattened lugs at the extremities of the bar, as shown in Fig. 3, have been removed and after the blank has been straightened to remove the arched or bowed configuration.

Fig. 6 shows a bar, with its ends flattened in acco-rdance with this invention, bent upon itself to show the mannerin which the center of the bar is maintained in a single plane throughout its entire length, and

Fig. 7 is a View similar to Fig. 6 but illustrating a bar in which the bar has been bowed laterallyY during the end flattening operation so as to illustrate the angular position of the ends of said bar when it is bent upon itself.

Referring to the drawing, l designates a fixed die member and Il a movable die member, be-` tween which the ends of a heated bar are adapted to be flattened. The top face ofthe fixed die member comprises a horizontal central portion l2 and downwardly curved portions I3--I3 which merge into horizontal portions lll- I4 at the ends of the die. The movable die member is formed with end portions having pressing faces l-l5 which incline downwardly and-outwardly insaccordance with the taper desired for the flattened .end portionsl--IG of the bar. Y The bar, designated 9 in Fig. 1, having been heated to a suitable temperature, is positioned between the die members l0 and Il so that the middle portion of the bar will rest on the horizontal central face I2 of the xed die member and the opposite ends of the bar will be spaced from the surfaces i3 and i4 of the die. During `the rst portion of the movement of the die member H in the direction to exert flattening pressure onV the end portions of the bar, the bar is bent downwardly from the full line position of Fig. 1 to approximately the position indicated in dotted lines. The intermediate portion of the bar being supported at the point designated l'l-I'l on the fixed die, but being free to move upwardly, assumes an upwardly bowed configuration during the downward bending of the end portions of the bar. An approximation of this bowed condition is shown in dotted lines in Fig. l.

During the above mentioned initial'bending of the bar, the edge portions i8 of the -rnovable die member cut into the upper face of the bar near its ends to approximately the position indicated in dotted lines in Fig. 1. The partially formed lugs IQ--IS on the bar, being engaged by the edges IB--lS of the movable die, hold the ends of the bar against inward movement during the application o-f further pressure on the bar.

-The continued movement of the movable die Vtoward the position indicated in Fig. 2 bends and presses the bar into firm contact with the downwardly curved surfaces l3-I3 and the horizontal end surfaces |4--|4. This continued bending and pressing operation, while holding the ends of the bar restrained from inward movement, resists the tendency of the bar to be distorted laterally by the horizontal compressive force exerted lengthwise of the bar by reason of the angularly disposed surfaces l5-I 5 displacing the metal at the ends of the bar. Lateral distortion of the bar is further prevented by reason of the initially bowed configuration imparted to the bar. By reasonof the vertically bowed conguration of the bar, any distortion of the intermediate portion of the bar by reason of the lengthwise compressive force above referred to, such distortion will follow the general contour of the arched bar and therefore will not disturb the longitudinal center of theV bar with relation to the center of the flattened end portion.

When the ends of the bar are flattened to increase the width and decrease the thickness toward the end of the bar, as herein described, the longitudinal center of the bar, when viewed in plan, as shown. in Figs. 4 and 6, is maintained in the same plane throughout the entire length of the bar. This condition is important, not only because of the difliculties involved in straightening uncontrolled and irregular lateral bows but because such a condition is important when, the bar is used in situations in which an end of the bar is bent ,upon itself in the manner indicated in Fig. 6 of the drawing. When the center of the bar is in the same plane throughout its entire length, either or both ends of the bar may be bent to hook form, as indicated in Fig. 6, and the ends will be in alignment with each other and their longitudinal centers will be in alignment with the center of the bar. However, if there should be a slight lateral bow to the bar and it is bent upon itself, the bent portion will stand at an angle, when viewed in plan, to the other portion of the bar, as shown in Fig. 7.

After the ends of the bar have been flattened, as shown in Fig. 2, the unflattened lug portions Iii- I 9 may be sheared from the'bar in any suitable manner. If the use of the bar is such as to make it desirable to remove the vertically bowed configuration, the bar can be readily straightened by applying suitable pressure to the crest `of the bow while the flattened end portions rest on a suitable surface to prevent tilting of the bar.

VWe claim:

l. The method of producing a metal bar having.

flattened end portions which consists in pressing a heated bar between dies, bending the intermediate portion of the bar in a predetermined direction and simultaneously flattening the ends thereof, thereby producing an unbalanced ccndition in one plane and a balanced condition in another plane at right angles thereto, whereby any distortion of the bar, resulting from the lengthwise compressive force incident to the flattening pressure atthe ends of the bar, will follow the direction of the bend formed in the bar.

2. The method of producing a metal bar having flattened end portions which consists in pressing a heated bar between die members, bending the bar to a predetermined bowed configuration and forming lugs at opposite ends thereof adapted to engage one of said die members, holding the ends of the bar from inward movement, continuing application of the said bending and attening pressures to the desired extent while the ends of the bar are restrained from inward movement, and then severing the said lug portionsv from the opposite ends of the bar.

' the bar and thereafer restraining the ends of the bar from inward movement and applying further bending and flattening pressures to the bar.

4. The method of producing a metal bar having flattened end portions which gradually decrease in thickness and increase in width toward the ends of the bar which includes bending the bar to an arched configuration and thereafter simultaneously pressing the end portions of the bar between dies, the pressing faces of which converge toward the ends of the bar; whereby any distortion of the bar by the forces incident to the atte'ning pressures of the inclined die faces on the bar will follow the direction of the bow initially formed in the bar.

5. The method of lproducing a metal bar having attened end portions which gradually decrease in thickness and increase in width toward the ends of the bar, which includes bending the bar to a predetermined bowed configuration, supporting the intermediate portion of the bar between pressing dies-permitting further bowing movement to the bar, holding the end portions of the bar against inward movement and applying flattening pressure to opposite ends of the bar simultaneously; whereby the lengthwise compressive forces incident to the flattening pressure at the ends of the bar impart further bowing movement to the bar.

6. The method of producing a metal bar having flattened end portions which gradually decrease in thickness and increase in width toward the ends of the bar, which includes bending' the bar to a predetermined bowed configuration and forming lugs at opposite ends of this bar adapted to engage portions of a pressing die, restraining inward movement of the ends of the bar, and thereafter applying further flattening pressure to the end portions thereof, whereby any distortion of the intermediate portion of the bar incldent to the attening displacement of metal at the ends will follow the direction of the initial bow formed in the bar.

7. The method of producing a metal bar having flattened end portions which gradually decrease in thickness and increase in width toward the ends of the bar, which includes bending the bar to a predetermined bowed conguration and forming lugs at opposite ends of this bar adapted to engage portions of a pressing die, restraining inward movement of the ends of the bar, and thereafter applying further flattening pressure to the end portions thereof, whereby any distortion of the intermediate portion of the bar incident to the flattening displacement of metal at the ends will follow the direction of the initial bow formed in the bar, then severing the unflattened lug portions from the bar and applying pressure to the crest of the bow in the bar so as to straighten thesame.

HAROLD G. WARR.' RICHARD A.v MCLAUGHLIN. 

